As a bookend to the thread. Got the wife's truck back from the shop. $543 to replace the thermostat (they got the parts). Better than the $802 the dealer wanted I suppose. I know I could have done the water pump, thermostat, expansion tank, and associated hoses for that price... but that's how it goes. My back surgery recovery precludes any attempt at doing repairs myself. The wife would kill me if she caught me in the garage right now.
At any rate they scanned the whole truck and gave it a clean bill of health. The only error they pulled is for expired differential fluid, which I was aware of also. I have a pint of that here and I will do that myself in another couple weeks (hopefully) as they wanted $175ish to do that service. The cold starts seem easier after the glow plugs and module, and the acceleration "feels" better now that the engine is reaching operating temperature. We'll see how the mileage trends now.
Question though. I believe Carly can monitor regens. What should I be looking for now with that? How often do they occur, etc? I think I can also purchase (in app) the ability to force a regen. Is that something I should do? Thanks all for the input.